With the age groups, there is more variation in NTRP level. Here in central Florida, the 30s and 40s age groups usually range from 4.0 to 5.0. I prefer the NTRP tournaments to be certain I get competitive matches.

When you look at a USTA tournament, if it's only say Men's 40, then it's a "open" tournament meaning all levels are allowed to play. The players that enter these tournaments are 4.5-5.0 or better, if you want to stay competitive play tournaments that designate NTRP 4.0.